Optical element



FIG. 1 is a front, top, and right side perspective view of an optical element;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a back elevation view thereof;

FIG. 4 is a top plan view thereof;

FIG. 5 is a bottom plan view thereof;

FIG. 6 is a right side elevation view thereof; and,

FIG. 7 is a left side elevation view thereof.

The broken lines depict unclaimed portions of a design for an optical element and form no part of the claimed design. 

CLAIM The ornamental design for an optical element, as shown and described. 